Claude API

How do you set up API key authentication vs. OAuth in Claude?

QUICK ANSWER

API keys are best for back-end applications using secret environment keys. OAuth 2.0 is required for client-facing integrations on the Anthropic Console, allowing individual users to sign in and run requests on their own accounts.

Authentication Selection Guide

  • API Keys: Simple authentication header. Store in environment variables (e.g., ANTHROPIC_API_KEY). Ideal for server-to-server calls and automated pipelines.
  • OAuth 2.0: Best when building an app where users pay for their own LLM usage. Users log in via Anthropic OAuth flows, granting your app token rights.
Verified against: Anthropic Console v2